The son of a former BSP MP was booked for allegedly brandishing a gun at guests and threatening them in the foyer of a five-star hotel here, a video of which went viral on the social media, police said Tuesday.

The Delhi Police has also sent a show-cause notice to the hotel for alleged negligence in the matter.

The accused, Ashish Pandey, hails from Lucknow and is the son of former Bahujan Samaj Party (BSP) MP Rakesh Pandey. His brother, Ritesh Pandey, is an MLA in Uttar Pradesh.

The police said an FIR was lodged under the Arms Act and sections of the IPC, including those related to causing hurt (323), criminal intimidation (506) and using force with the intent to outrage the modesty of a woman (354).

Initially, the case was registered under the Arms Act and the IPC sections were added to it later, the police said.

"The police have registered a case. We are coordinating with the Uttar Pradesh police and teams are looking out for him (Pandey)," Joint Commissioner of Police (New Delhi) Ajay Chaudhary said.

"We have added the relevant sections based on the video. A Look-Out Circular (LOC) has been issued," he added.

A Delhi Police team reached Lucknow Tuesday in connection with the probe into the incident.

"A Delhi Police team has arrived here and the UP police is extending full cooperation," Deputy Inspector General (law and order) Pravin Kumar said in Lucknow.

The Delhi Police said the complaint about the incident was received Monday from the assistant security manager of the Hyatt Regency hotel in RK Puram.

The hotel maintained that it was taking the incident "seriously" and would cooperate with the authorities in the probe.

The Aam Aadmi Party (AAP) targeted the Centre, which controlled the Delhi Police, over the issue of law and order in the national capital.

Party spokesperson Dilip Pandey said the BJP-led Centre should answer why it had no control over the system, which it supervised through the lieutenant governor (LG), and asked what steps were being taken by the police to check the growing incidents of crime in the city.

Delhi BJP chief Manoj Tiwari said there was CCTV footage of the incident and a proper probe should be conducted.

After the video of the incident went viral, Union Minister of State for Home Affairs Kiren Rijiju said the police had initiated action in the case.

"The Delhi Police has initiated action on this incident which is also being shown in the media. An FIR has been registered under the Arms Act and IPC. Strong and appropriate action will be taken. Also verifying the identity of others," he tweeted.

Meanwhile, the BSP distanced itself from the controversy.

"Ashish Pandey is not a BSP leader or member. There is a law-and-order machinery and action should be taken against anyone who breaks law," party leader Sudhindra Bhadoria said.

Congress leader Sonia Gandhi's son-in-law Robert Vadra also expressed serious concern over the law-and-order situation in the city following the incident.

The incident occurred in the early hours of Sunday, the police said.

In the video, Pandey is purportedly seen brandishing a pistol in the foyer of the hotel, a police officer said.

One of the guests at the hotel told a news channel that the accused, holding the pistol, walked up to him and hurled abuses.

"A man with a gun hurled abuses at us and walked up threateningly. I was intimidated and scared. The hotel staff was present at the spot. They tried to intervene but could not as they were also scared," he claimed.

Meanwhile, former Congress MLA Kanwar Karan Singh said his son, who was shown a gun by Pandey, was in "trauma" after the incident and that was the reason why he did not inform the police.

Singh said his son had recorded his statement with the police and the family had full faith in the law of the land.

The police said the security staff of the hotel told them that the accused and the victims were partying at a nightclub in the hotel.

One of the victim's female friends was throwing up in the women's washroom and he had gone to check on her when Pandey's women friends also came there and an argument ensued, the police said.

It continued even after they came out of the washroom, following which Pandey got the gun from his BMW car and allegedly threatened the victims.

A woman accompanying the accused abused the victims and called them "transgenders", a senior officer privy to the probe said.

It was suspected that both the parties involved were drunk at the time of the incident, he added.

"No PCR call was made by any of the parties or even the hotel authorities. It is negligence on part of the hotel as something major could have happened," another officer privy to the probe said.

He added that by not alerting the police about the incident promptly, the hotel too was guilty of facilitating the accused to flee.

"We are exploring legal options and will also inform our licensing branch that will see what action can be taken against the hotel," the officer said.

He added that after the video went viral, the police contacted the hotel authorities and then they lodged the complaint.

"No complaint was lodged by the victim and the hotel staff the same day. There is negligence on the part of the victim, the hotel authorities and the accused," Chaudhary said.

The police said whether the accused was carrying a licensed weapon or not would be known once he was caught.